Hand-held power finisher

ABSTRACT

A hand-held power finisher includes a handle for being gripped by a user, and a mounting hub attached for rotation at one end of the handle. A plurality of blades extend outwardly from the mounting hub. A drive shaft is operatively connected to the mounting hub. A motor is operatively connected to the drive shaft, and is adapted for rotating the mounting hub and blades relative to the handle. The blades engage and finish a solid surface.

TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

This invention relates to a hand-held power finisher especiallyapplicable for finishing solid surfaces, such as concrete countertops.Concrete countertops are relatively lightweight, come in limitlesscolors and textures, are essentially seamless, and can be formed into anumber of interesting complex shapes and designs.

Concrete countertops are becoming more popular across the country. Themanufacturing process, however, is labor intensive and requiresintricate hand work in making the forms. The forms are either pre-castin a workshop where conditions are controlled, or built on-site tocustom design the countertop to a particular client's needs includingradius edges, curved corners, and the like. The countertops are made ofcement, lightweight aggregates, and a combination of additives such asfiber reinforcement, silica fume, pozzolan, and acrylic. Some type ofreinforcement is generally used, such as structural steel, wire mesh,fiberglass, and/or fibers.

After curing, the countertops are typically finished using progressivelyfiner polishing stones, and then sealed using an epoxy sealer. Thepolishing stones grind off the cement surface “skin” which forms on allconcrete. This achieves two important objectives; durability and beauty.The skin creates a unwanted barrier which would otherwise prevent theprotective sealer from penetrating the concrete. Grinding and honing theconcrete also reveals the complex patterns of aggregate and coloredcement that would lie hidden beneath the drab, monochromatic cementskin. While polishing stones are generally effective, the time and laborrequired to grind and hone the concrete form is substantial.

SUMMARY OF INVENTION

Therefore, it is an object of the invention to provide a hand-held powerfinisher which is especially applicable for finishing solid surfaces,such as concrete countertops.

It is another object of the invention to provide a hand-held powerfinisher which reduces the time and labor required to grind and honesolid surfaces.

It is another object of the invention to provide a hand-held powerfinisher which utilities rotating finishing blades.

It is another object of the invention to provide a hand-held powerfinisher which has a large pitch-control range giving complete controlover finishing and floating for application versatility duringoperation.

It is another object of the invention to provide a hand-held powerfinisher transmits power to the finishing blades through gears.

It is another object of the invention to provide a hand-held powerfinisher which produces a swirl-free flat finish.

It is another object of the invention to provide a hand-held powerfinisher which is applicable for finishing concrete, terrazzo, marble,granite, and other solid surfaces.

It is another object of the invention to provide a hand-held powerfinisher which utilizes replaceable and exchangeable finishing blades.

It is another object of the invention to provide a hand-held powerfinisher which utilizes combination blades for rough surfaces andfinishing blades for final smoothing.

These and other objects of the present invention are achieved in thepreferred embodiments disclosed below by providing a hand-held powerfinisher. The power finisher includes a handle for being gripped by auser, and a mounting hub attached for rotation at one end of the handle.A plurality of blades extend outwardly from the mounting hub. A driveshaft is operatively connected to the mounting hub. A motor isoperatively connected to the drive shaft, and is adapted for rotatingthe mounting hub and blades relative to the handle. The blades engageand finish a solid surface.

According to another preferred embodiment of the invention, a light isprovided for illuminating the solid surface.

According to another preferred embodiment of the invention, an air sprayis provided for directing air flow towards the solid surface.

According to another preferred embodiment of the invention, a waterspray is provided for spraying a water mist upon the solid surface.

According to another preferred embodiment of the invention, means areprovided for adjusting the pitch of each of the plurality of blades.

Preferably, the pitch of each of the plurality of blades is adjustablewithin a range of 0-40 degrees.

According to another preferred embodiment of the invention, each of theplurality of blades has a textured grit surface adapted for engaging thesolid surface.

According to another preferred embodiment of the invention, the powerfinisher includes more than three blades.

According to another preferred embodiment of the invention, each of theplurality of blades has a length less than 8 inches.

According to another preferred embodiment of the invention, each of theplurality of blades has a width less than 4 inches.

According to another preferred embodiment of the invention, the motor isoperable for rotating the blades at speeds greater than 50 rpm.

BRIEF DESCRIPTION OF THE DRAWINGS

Some of the objects of the invention have been set forth above. Otherobjects and advantages of the invention will appear as the descriptionproceeds when taken in conjunction with the following drawings, inwhich:

FIG. 1 is a perspective view of a hand-held power finisher according toone preferred embodiment of the present invention;

FIG. 2 is a schematic view illustrating the gear assembly adapted fordriving the finishing blades of the power finisher;

FIG. 3 is a fragmentary perspective view of the power finisher showingthe gear key of the tilt adjustment shaft in a normal position away fromthe blade mounting hub; and

FIG. 4 is a fragmentary perspective view of the power finisher showingthe tilt-adjustment shaft in a depressed condition inserting the gearkey into a keyway formed with the tilt-adjustment gear, anddemonstrating tilt adjustment of the finisher blades upon rotation ofthe tilt control knob.

DESCRIPTION OF THE PREFERRED EMBODIMENTS AND BEST MODE

Referring now specifically to the drawings, a hand-held power finisheraccording to the present invention is illustrated in FIG. 1, and showngenerally at reference numeral 10. The power finisher 10 is especiallyapplicable for sanding, grinding, honing, polishing, and cleaning solidsurface countertops constructed of concrete, terrazzo, marble, orgranite. The finisher 10 comprises an ergonomic, contoured handle 11with a number of optional accessories including a water/air spray 12 andlight 14. The light illuminates an area of the solid surface beingfinished. The water spray applies a light mist upon the solid surfaceduring finishing, while the air spray promotes drying. The water and airsprays are emitted from a single nozzle, and separately activated usingany suitable and conventional triggering means (not shown).

As best shown in FIGS. 1 and 2, a number of radially-extending finishingblades 15 are carried by a mounting hub 16 arranged at one end of thehandle 11. The mounting hub 16 is attached for rotation relative to thehandle 11, and is actuated by a standard gear assembly including a driveshaft 17, spur gear 18, and motor 19. The spur gear 18 operativelyengages a complementary gear 21 formed with the mounting hub 16. Themotor 19 is housed within the handle 11, and is operatively connected tothe drive shaft 17 for rotating the mounting hub 16 and attachedfinishing blades 15. The motor may be any suitable AC or DC electricmotor with an operating voltage of 115v/60 Hz and current of between5-10 Amps. Preferably, the mounting hub 16 and blades 15 rotate atspeeds ranging from 50-450 rpm. Alternatively, the finisher 10 mayutilize a small pneumatic or hydraulic motor. The motor 19 may beactivated by any conventional means including a simple on-off switch, ora finger trigger allowing variable speed adjustment.

The blades 15 are replaceable and exchangeable, and preferably have atextured or grit surface for engaging the solid surface being finished.The surface-engaging portion of the blade 15 may comprise a flexiblefiber mesh impregnated with diamond powder, a resin diamond, a rigidaluminum, or semi-rigid rubber. The grit ranges from 70-3000. For honingand polishing concrete, for example, the blade grit is preferablybetween 70 and 1800. According to one embodiment, each blade 15 isapproximately 6-inches long and approximately 3-inches wide.

Referring to FIGS. 2, 3, and 4, each blade 15 is carried on an elongatedarm 22 secured to the mounting hub 16. Respective bevel gears 23 arelocated at proximal ends of the blade arms 22, and are positioned inmeshing alignment with a complementary bevel gear 24 located inside themounting hub 16. A tilt-adjustment shaft 25 is axially-biased away fromthe gear 24, and has an integrally-formed gear key 25A designed forinserting into a complementary shaped keyway 24A formed through thetilt-adjustment gear 24. When the drive motor 19 is stopped or idle, thetilt-adjustment shaft 25 is depressed, as indicated by arrow 26, causingthe gear key 25A to insert into the keyway 24A of the tilt-adjustmentgear 24. With the gears 23 and 24 engaged, a knob 28 at an opposite endof the tilt-adjustment shaft 25 is manually rotated, as indicated byarrow 29, to actuate the gears 23, 24 and simultaneously adjust the tiltangle of blades 15, as indicated at arrows 31 and 32. Once adjusted, theshaft 25 retracts to its normal position away from the tilt-adjustmentgear 24. Preferably, the tilt-adjustment gear 24 has a built-in ratchetmechanism which restricts its rotation in one direction, thereby fixingthe tilt orientation of the blades 15 during operation of the finisher10. Thus, as the rotating tilted blades 15 are applied against the solidsurface, the meshing arm gears 23 and tilt-adjustment gear 24 cooperateto prevent flattening of the blade angle. Preferably, the blade angle isadjustable between 0-40 degrees. Examples of power trowels with tiltadjustable blades are provided in prior U.S. Pat. Nos. 6,739,798;5,405,216; and 4,673,311. The complete disclosures of these patents areincorporated herein by this reference.

A hand-held power finisher is described above. Various details of theinvention may be changed without departing from its scope. Furthermore,the foregoing description of the preferred embodiment of the inventionand best mode for practicing the invention are provided for the purposeof illustration only and not for the purpose of limitation-the inventionbeing defined by the claims.

1. A hand-held power finisher, comprising: (a) a handle for beinggripped by a user; (b) a mounting hub attached for rotation at one endof said handle; (c) a plurality of blades extending outwardly from saidmounting hub; (d) a drive shaft operatively connected to said mountinghub; and (e) a motor operatively connected to said drive shaft, andadapted for rotating said mounting hub and blades relative to saidhandle, said blades adapted for engaging and finishing a solid surface.2. A hand-held power finisher according to claim 1, and comprising alight adapted for illuminating the solid surface.
 3. A hand-held powerfinisher according to claim 1, and comprising an air spray adapted fordirecting air flow towards the solid surface.
 4. A hand-held powerfinisher according to claim 1, and comprising a water spray adapted forspraying a water mist upon the solid surface.
 5. A hand-held powerfinisher according to claim 1, and comprising means for adjusting thepitch of each of said plurality of blades.
 6. A hand-held power finisheraccording to claim 5, wherein the pitch of each of said plurality ofblades is adjustable within a range of 0-40 degrees.
 7. A hand-heldpower finisher according to claim 1, wherein each of said plurality ofblades comprises a textured grit surface adapted for engaging the solidsurface.
 8. A hand-held power finisher according to claim 1, whereinsaid plurality of blades comprises greater than three blades.
 9. Ahand-held power finisher according to claim 1, wherein each of saidplurality of blades has a length less than 8 inches.
 10. A hand-heldpower finisher according to claim 1, wherein each of said plurality ofblades has a width less than 4 inches.
 11. A hand-held power finisheraccording to claim 1, wherein said motor is operable for rotating saidblades at speeds greater than 50 rpm.
 12. A hand-held power finisher,comprising: (a) a handle for being gripped by a user; (b) a mounting hubattached for rotation at one end of said handle; (c) at least threeblades extending outwardly from said mounting hub; (d) a drive shaftoperatively connected to said mounting hub; (e) a motor operativelyconnected to said drive shaft, and adapted for rotating said mountinghub and blades relative to said handle, said blades adapted for engagingand finishing a solid surface; and (f) means for adjusting the pitch ofeach of said blades within a range of 0-40 degrees.
 13. A hand-heldpower finisher according to claim 12, and comprising a light adapted forilluminating the solid surface.
 14. A hand-held power finisher accordingto claim 12, and comprising an air spray adapted for directing air flowtowards the solid surface.
 15. A hand-held power finisher according toclaim 12, and comprising a water spray adapted for spraying a water mistupon the solid surface.
 16. A hand-held power finisher according toclaim 12, wherein each of said plurality of blades comprises a texturedgrit surface adapted for engaging the solid surface.
 17. A hand-heldpower finisher according to claim 12, wherein each of said plurality ofblades has a length less than 8 inches.
 18. A hand-held power finisheraccording to claim 12, wherein each of said plurality of blades has awidth less than 4 inches.
 19. A hand-held power finisher according toclaim 12, wherein said motor is operable for rotating said blades atspeeds greater than 50 rpm.
 20. A hand-held power finisher, comprising:(a) a handle for being gripped by a user; (b) a mounting hub attachedfor rotation at one end of said handle; (c) at least three bladesextending outwardly from said mounting hub; (d) a drive shaftoperatively connected to said mounting hub; (e) a motor operativelyconnected to said drive shaft, and adapted for rotating said mountinghub and blades relative to said handle, said blades adapted for engagingand finishing a solid surface; (f) means for adjusting the pitch of eachof said blades within a range of 0-40 degrees; (g) a light adapted forilluminating the solid surface; (h) an air spray adapted for directingair flow towards the solid surface; and (i) a water spray adapted forspraying a water mist upon the solid surface.